Currently, PDP device is in practical use as a flat display being high-luminance, thin, and capable of large-screen display, and its overall operation properties have been improved along with improving display quality. PDP is a display device which performs display using discharges, and generally configured by several hundreds of thousands to several millions of pixels. Generally, in display of an AC-type PDP device, each field that becomes a screen is configured by a plurality of subfields having different luminance weightings. Each subfield is configured by, for example, a reset period, an address period, and a sustain period.
Reset period is a period for generating discharges at all cells and adjusting the amount of charges in the cell to smoothly perform a discharge in a subsequent address period. Address period is a period for performing a discharge (address discharge) for selecting a target On cell in a display area by applying a select pulse to a scan electrode and an address electrode and generating charges. Note that, it is not limited to the method of generating discharges at target On cells (write address method), and there is also a method of reducing charges at cells by generating discharges at target Off cells (erase address method). Subsequent sustain period is a period for performing display by actually lighting (emission), in which repetitive discharges (sustain discharges) are performed by alternately applying pulses across a scan electrode (Y) and a sustain electrode (X) (Y-X) at the cells selected and discharged in the address period just before the sustain period. Especially, the reset period has a role to generate continuous minute discharges to lead to a next address period and align discharge voltages in the address period by adjusting charges in the cells.
To form charges in a reset period, conventionally, there have been applied a waveform whose voltage is gradually raised (rising reset waveform), and subsequently, a waveform whose voltage is gradually fallen (falling reset waveform) as waveforms of the reset period (reset waveform). Such reset waveforms can perform finer control as the slope of the waveforms is smaller (gentler), thereby achieving stable discharge and charge generation. And, as an application of the reset waveforms, the rising and falling waveforms have been made to have stepwise slopes, where a first slope is steep and a second slope is gentle, so that the smaller the slope of the second slope is, the finer the control is. Such a technique is described in Japanese Patent Application Laid-Open Publication No. 2004-62207 (Patent Document 1).
And, as a method of generating a slope waveform, there is a method to apply voltage intermittently while changing voltage gradually to a predetermined voltage. Such a technique is described in Japanese Patent Application Laid-Open Publication No. 2005-122152 (Patent Document 2).
Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2004-62207
Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2005-122152